1. Field of the Invention
The present invention relates generally to a dental mask that is designed to be worn by members of a dental staff, and more specifically to a dental mask having dual chambers, one for inhaling and the other for exhaling.
2. Description of the Prior Art
The environment in a dental office can be detrimental to the health of both the patient and the dental staff. In addition to harmful aerosols, which studies have shown may contain up to 100,000 bacteria per cubic foot of air within three feet of the patient, the dental office may regularly contain nitrous gases, disinfectant fumes, mercury vapors, sterilization fumes, tooth dusts, fillings dust, sulfates, polyether fumes, viruses, saliva droplets, etc. The aerosols generated by air polishers are particularly harmful. High speed cutting instruments (200,000 to 300,000 rpm) generate considerable heat which can cause injury to the tooth pulp. To prevent this, water spray is employed as a coolant and a lubricant. As a result, there are microbial aerosols which are generated from the patient""s mouth during dental operations which are comparable in bacterial concentrations to those produced during coughing and sneezing.
Transmission of infection requires a series of factors: a source of reservoir for the pathogen, a pathogen of sufficient infectivity and number, a mode of escape from the host, and a portal of entry. Infection-control techniques seek to eliminate one or more links in the chain of infection. Barrier products such as masks are viewed as a means of protecting both patients and dental staff from pathogens in potentially infectious sprays, splash, and spatter. Masks must be worn when risk of spray or splash of fluids can be anticipated. The FDA recommends that surgical masks have a 95 percent or greater bacterial filtration efficiency. Masks of glass or synthetic fiber demonstrate great filtering efficiency. However, almost all the particles that can penetrate an efficient filtration mask are so small in diameter that they will be hazardous if they penetrate the alveoli of the human lungs. It is important to consider that bacterial aerosols do remain airborne for many hours after certain dental procedures, unless they are removed by an efficient ventilation system.
The prior art is well documented with masks that attempt to solve the above problems. In addition to filtration, masks seek to solve the problems such as fogging of eye glasses. Some short comings in prior art masks are masks that do not adapt very well to different sizes and shapes of faces, especially along the ridge of the nose or chin. Many masks do not provide any measure near the 95 percent FDA requirement. The fogging of glasses is due to the carbon dioxide along with warm moisture that accompanies the breath in exhalation. Lack of proper venting of the mask may cause members of the dental staff to breath in his/her own exhaled carbon dioxide, thereby diminishing the percentage of oxygen with each breath. This lack of oxygen can cause symptoms of hypoxia; that is the state in which there is inadequate oxygen to satisfactory meet the needs of tissues. The effects of long term state of hypoxia can be seen in drowsiness, inattentiveness, apathy, delayed reaction time, severe fatigue and reduced work capacity.
For an average person the intake of air with each inhaled breath is approximately 500 ml, of which about 150 ml is expired before it ever reaches the alveoli. This 150 ml of air is considered useless from the point of view of oxygenating the blood and the respiratory passageways are thereby called dead space. Thus for each breath only about 350 ml of air are actually utilized. Since the average person needs about 4200 ml of new air per minute, this will require about 12 breaths per minute. In a dental procedure, if the mask does not properly ventilate the exhaled breath, then the dentist will breathe in a percentage of his own carbon dioxide with each breath, thereby requiring far more respirations per minute to satisfy his/her oxygen requirements to thereby prevent a state of transient hypoxia.
There are basically two types of masks used in dental procedures. One is a semirigid cup-shaped mask that fits over the nose and mouth, usually with some form of a malleable soft metal to pinch over the ridge of the nose to prevent fogging. The other is a softer mask which is predominantly made of pleated layers of filter material. The main advantage of the semirigid mask is that it will keep the inner surface away from the wearer""s face. The biggest disadvantage is that both fresh air and exhale breath can mingle together in the chamber. The main advantage of the softer pleated mask is in comfort to the wearer. The problem is that, when the wearer inhales, these masks have a tendency to be drawn very close to the face, thereby creating a somewhat claustrophobic feeling, as well as the problem created when a very strong inhalation adheres a large amount of particles at the mouth or nose sites.
U.S. Pat. No. 5,307,796 issued to Kronzer et al. on May 3, 1994, discloses a face mask of the semirigid type that is very commonly found in dental offices. It is generally the least expensive and has only one chamber.
U.S. Pat. No. 4,951,662 issued to Townsend, Jr. on Aug. 28, 1990, teaches the use of a mask that seeks to eliminate fogging by having a housing adjacent to the mask which has a volume considerably larger than the mask volume, thereby permitting the breath to be substantially removed during each breathing cycle. Townsend, Jr. shows a loop encircling the wearer""s neck and suggests the use of a circulating fan to draw in fresh air.
U.S. Pat. No. 5,699,792 issued to Reese et al. on Dec. 23, 1997, discloses a face mask with enhanced facial sealing. The mask to Reese is typical of the softer pleated masks which are available and address the need for improved facial sealing to protect against bacteria, viruses, particles, blood droplets, contaminants etc.
U.S. Pat. No. 4,606,341 issued to Hubbard et al. addresses the importance of keeping the mask from collapsing against the wearer""s face, but this patent falls short of suggesting dual chambers.
U.S. Pat. No. 5,406,944 issued to Gazzara on Apr. 18, 1995, teaches the use of an adjustable face protector which provides increased prevention from contaminated fluids. The present invention addresses the use of shields as well as filtration capturing and reflective panels.
U.S. Pat. No. 5,584,078 issued to Saboory on Dec. 17, 1996, suggests the use of a detachable/disposable face shield that one can clip to a surgical mask. This patent addresses the need for a shield, mainly for the eyes, in which can be used according to the needs of the wearer.
None of the above inventions and Patents, taken either singly or in combination, is given to describe the instant invention as claimed.
Accordingly, the above problems and difficulties are obviated by the present invention which provides for a primary disposable face mask, as well as a reusable frame to be used by medical personnel, especially those in the dental profession.
More particularly, the present invention is comprised of a face mask having dual chambers. An upper chamber for inhalation of fresh air and a lower chamber for exhalation of carbon dioxide ladened breath. The lower chamber having vent flap openings on the cheek sides for the removal of spent air. Embodiments of the present invention may have tubing attached to the vent openings for releasing of the exhaled breath away from the work site. In some embodiments the tubing can be attached to an exhaust suction lines or filtration systems. The dual chambers are created by mask design and by having a band of soft elastic material across the philtrum (area between naris and upper lip) which effectively seals the two chambers from each other. By inhaling through the upper chamber, the incoming air to the lungs will not be contaminated or mixed with exhaled carbon dioxide and other unwanted substances. In lieu of the vent flaps of the preferred embodiment, some embodiments may utilize vent openings being attachable to tubing that removes the exhaled air away from the work site and possible to a filtration system, the air supply at the work site will thereby be effectively improved in quality. The lower chamber will be basically used for exhalation of carbon dioxide, which can also be aided by connecting the tubing to an evacuation device such as a suction line or fan.
The mask of the present invention provides for a mask that is basically semirigid in both the upper and lower chambers. Primary reason for this design is to incorporate the benefits of the semirigid mask in which the surface of such a mask is kept away from the skin of the wearer, thereby preventing any claustrophobic feeling or difficulty in breathing. The fan type soft mask of the prior art has an inherent flaw in that when air is inhaled, the soft mask material is sucked into the mouth area along with the air. The present invention, by utilizing the semirigid construction in the upper chamber will not experience that problem.
The present invention provides for a redesign of the filtration aspect of the mask. It establishes three areas of filtration. A primary filtration area whereby the most effective filtration must be accomplished. This is primarily in the center area of the mask over the nose, nasal passages and mouth. The second filtration area is located around the primary area, which is in the cheek area of the face. The third filtration area is mostly located in the fringe areas. It is generally acknowledged that the main area of filtration must be in the center of the mask. The present invention will incorporate a rugged, high surface area, created by peaks and valleys in the surface of the mask in this primary area. Larger particles will deposit on the peaks, which may have adhesive characteristics and smaller particles, usually viruses, bacteria and gases, will be picked up in the valley area. The present invention also acknowledges that when these particles impinge upon the mask surface that it would be beneficial that they be retained there rather than reintroduced into the area again. The present invention will incorporate a mantle projection extending outwardly from the surface of the lower chamber to provide a measure of protection to the breathing zone. The mantle having an adhesive band section which, besides trapping and retaining particles, can be manufactured so as to indicate color change. This color change is a visual indicator of when the mask needs changing. It is advisable that the mask be changed frequently, and the changing color will serve as a reminder to do so.
The present invention will improve visibility by eliminating fogging to the wearer""s glasses. The mask of the present invention will encourage the wearer to take in air only in the upper chamber and to discharge the warm, moist exhaled breath in the lower chamber. Removing spent air via the lower chamber through venting flaps or tubing will by design prevent fogging of wearer""s glasses.
The present invention realizes that some procedures will require an increased level of safety for the health personnel and thereby it is acknowledged that often it is desirable to be able to place additional insertion pads directly into the chambers.
Also an embodiment of the present invention will have means for changing filtration pads without discarding the entire mask. This will involve making the frame of the basic mask reusable. The frame therefore could be manufactured of a cloth-covered sponge material molded about the perimeter. This would make it flexible and adaptable to irregularities of the face and also provide increased comfort and sealing, while also allowing for the discarding of less expensive filtration materials. The frame will utilize periphery clips the entire perimeter, while the reusable filter pads will have cooperating curved recesses for press-fitting onto the frame (in a manner that a lid snaps onto a cup). This can permit use of a higher quality material, one that is more comfortable to the skin and yet still provide a mask with disposable filtration elements.
The present invention will have means for allowing the user to snap protective shields, light deflection shields, and tinted shields. The protective shield is a first line of defense from air borne particles which fly from the work site. The shield is pitched away from the face and mask, to prevent closure, sweating and breathing difficulties. The shields can also provide a measure of protection from ultraviolet rays, especially those rays that are used in curing of composite materials, fiberoptic lights and the bright lights illuminating the field.
The present invention will have vent flaps which open and close on pressure gradients. The vent flaps are located in both chambers. The mask itself extending further to the sides of the face than prior art masks. This enables the mask to be more uniform and easier to adapt a seal therein.
The present invention will have means for attaching tubing which is positioned whereby the spent breath can be evacuated from the lower chamber. A powered device such as a suction line, fan or filtration system can be added to the distal end of the tubes for increased suction or ventilation.
An important object of the present invention is to provide a comfortable mask which will adapt to any size or shape face.
Another object of the present invention is to provide dual chambers, one mainly for inhalation and the other mainly for exhalation.
Another object of the invention is to incorporate the benefits of both semirigid mask materials with a perimeter frame comprising of comfortable, more durable materials.
An important object of the present invention is to utilize an adhesive band section that will not only entrap contaminants but which will retain them, and will indicate by color change when the mask needs to be changed.
An object of the present invention is to utilize a high surface area in the primary filtration area, whereby peaks and valleys in the outer surface will substantially increase the surface filtration area.
Another object of the present invention is to provide vent flaps and vent openings for the evacuation of the spent carbon dioxide. The vents being positioned whereby the venting will be directed posteriorly.
Still another object of present invention is to provide a mask that will have means for adapting facial protective shields, reflective shields and tinted shields.
Another object of the present invention is to provide a frame type gasket comprising of soft cloth, soft paper, or sponge like material for contact with the face, for enhanced conformation with different facial configurations and irregularities.
Another object of the present invention is extending the mask further to the sides of the face for better sealing.
Another object of the present invention is to provide a mask that can be manufactured of inexpensive components thereby providing a mask that will be economical to the user.
These and other objects will become readily apparent upon further review of the following specification and drawings.